Balanced slide-valve



(1&0 Model.)

' A. THOMSON.

BALANCED SLIDE VALVE. No. 361,382. Patented Apr. 19, 1887.

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UNITED STATES PATENT OFFICE.

ARCHIE THOMSON, OF GHATTANOOGA, TENNESSEE.

BALANCED SLIDE-VALVE.

SPECIFICATION forming part of Letters Patent No. 361,382, dated April 19, 1887.

Application filed October 8, 1886. Serial No. 215,707. (No model.)

To all whom it may concern: I

Be it known that I, AROHIETHOMSON, a resident of Chattanooga, in the county of Hamilton and Stateof Tennessee, have invented certain new and useful Improvements in Counter-Balanced Slide-Valves, ofwhich the following is a specification.

My invention relates to an improved slidevalve movement. I

The object of my invention is to provide a counter-balance piston connected to the valve by a link, so that the pressure upon the supplemental piston above the valve will relieve a portion of the pressure of the steam upon the valve.

The various features of my invention will be fully set forth in the description of the accompanying drawings, making a part of this specification, in which-- Figure l is a vertical longitudinal section of my improvement; Fig. 2, a transverse central section of the same.

1 represents the cylinder of a steam-engine; 2, the steam-ports leading from the valve to the cylinder.

3 represents the valve working across the orifices of the ports 2.

4 represents ledges projecting from the side a of the Valve.

5 represents a cylinder supported upon the top of the steam-chest 6, and supporting a supplemental piston-cylinder, 7.

8 represents a supplemental piston working" prevents the wearing and the tendency of the piston 8 to tip or cant, which would cause the link-movement to bind. I have made this guide-stem 14 hollow, and place therein a checkvalve, 15, so as to serve as an oiler.

16 represents a stuffing-box for the stem 14 to move in without leaking steam.

The stem 14 not only extends through the stuffing-box 16, but at its lower end the stem extends through the arched part 9 of the piston 8. The part of the stem passing through the arched part of the piston is pierced with a vertical passage, 14, so that oil can pass from the hollow stem upon the link-joints, thus oiling the link-joints, as well as the valve and piston.

Steam is admitted into the steam-chest, lifts,

of the steam-chest, so as to prevent any tend-' ency of this valve rising. The check-valve 15 is held closed whenever the steam is admitted into the steam-chest. When the steam is cut off, the valve drops, and oil may be admitted from the oil-cup 17, to pass down upon and oil the valves.

18 represents an orifice pierced in the stem 14, so as to admit the oil down into the chamber 19, to oil the supplemental piston 8. The link 10 may be slotted, so that when the steam is not in, the valve will move withoutworking the link;

I claim- 1. The combination of the valve-chest, the arched piston 8, the slide-valve 3, having its sides provided with the longitudinal flanges 4, extending upward adjacent to the cover of the valve-chest, and the link 10, connecting the arched piston and valve, substantially as described.

2. The combination, with the valve-chest, the cylinder 7, having the stuffingbox 16, the slide-valve 3, the arched piston 8, and the linkconnection 10, of the hollow stem 14, extending through thestuffing-box and through the arched part of the piston, and having the vertical passage ll and lateral passages 18, for oiling the link-joints, the slide-valve, and the piston, substantially as described. I

3. In combination with the steam-chest hav- ARCHIE THOMSON.

5 ing a cover, the supplemental piston 8, the

link 10, and the valve 3, provided with pro- In testimony whereof I have hereunto set 10 my hand this 5th day of October, 1886.

Witnesses:

jecting flanges 4, working adjacentto the steam- ROBERT ZAHNER, chest cover to prevent the Valve rising, substantially as described.

M. E. MILLIKAN. 

